I know there exist apps such as meterberry and tinymeter that show the battery discharge rate, but is there an app that shows this in the status bar? I keep checking it atleast 4-5 times a day and it'd be really helpful to have it in the status bar along with the battery %
OR perhaps I am not understanding what you are looking for
Where MeterBerry shows either the battery level, battery temperature or free memory icon in the notification banner... the OP wants an app that shows ADR in there.
OP, this isn't an exact solution, but a workaround might be assigning a convenience key on your device. I have my 'pause' button set to tiny meter (through another app, but I'm sure you could set the side keys just as well.)